fix(webapp): billing alert preview uses current limit instead of stale saved amount

[claude]

Requested by Iss · Slack thread

Testing

Added a regression test in apps/webapp/test/billingAlertsFormat.test.ts covering the raised-limit scenario, and ran the billingAlertsFormat test suite (26 tests passing). The new test fails against the previous behavior (returns the stale 3000) and passes with the fix (returns the current 30000).

Before: After raising the billing limit, the alert threshold preview still showed dollar amounts calculated against the previous limit until the user clicked "Update alerts" again.

After: The preview reflects the current saved billing limit immediately.

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Changelog

getAlertPreviewLimitCents no longer returns the alert record's snapshotted amount whenever saved percentage levels exist. It returns the snapshot only when it still matches the current effective/plan limit, and otherwise returns the current effectiveLimitCents, so the threshold preview follows the saved billing limit right away. Added a regression test.

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Generated by Claude Code

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Latest commit: 186a139

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[claude]

Closing as superseded — this preview bug is already fixed on main by #4328, which changed getAlertPreviewLimitCents to derive the percentage preview from the current limit. No need for this separate change.